1

CHAPTER 1

INTRODUCTION

1.1 GENERAL

The water requirements are linked with the density of population

and the growth of industrial activity. As the population and the industrial

activity increase, it is susceptible to have more possibilities of water scarcity.

Even though water is surplus on the earth, approximately 97% of the water

contains salt and it is not suitable for domestic (cooking, drinking, etc.),

construction and various industrial purposes. The remaining two percent of

water is in the form of ice and one percent of the total water is only usable

water, of which ground water accounts for 98% and the surface water

accounts for 2%. Therefore such a limited resource is very precious and it

needs to be utilized economically (Irshad Ahmad 2004). According to the

United Nation’s study, the world population and the industrial development

continue to surge and the availability of freshwater is on the decline and in the

next two decades many of the countries in South Asia, Middle East Asia and

Africa will face water crisis (Bosnic et al 2000).

Due to urbanization and industrialization, construction industry is

in the rapid pace of development in India. A large quantity of water is

required for the entire construction activity which includes mixing of concrete

ingredients, curing of concrete, washing of equipments etc. Both in developed

and in developing countries water depletion issues are the major problems and

hence an alternate has to be found out to replace the potable water used in the

2

construction industry with some other re-used industrial effluent. The ground

water level will not be affected if the waste water is used for construction

purpose.

The waste water let out from various industries such as tanneries,

textile processing units, rice mills, dairy farms, paper mills, etc., are

considered for re-using in the construction activity. More number of tanneries

and textile processing units are clustered in South India and a huge amount of

water is let out from the tanneries and textile processing units after processing

the raw materials. From a quantitative analysis, the water that is let out from

the textile and tannery industries after the processes are approximately 80,000

– 1,40,000 litres and 40,000 litres per ton production of processed clothes and

processed tannery products respectively (Garg 1998). All over India there are

approximately 2,000 tanneries and 5000 textile processing units located at

different centres which let out huge amount of water after processing

(Madhuri Raju and Tandon 1999). Even the treated water from tannery and

textile processing units cannot be used in the same industries because the

quality of the end products will be affected. Hence in this present study, the

feasibility of using the tannery and textile processed effluents in the

construction activity is examined distinctly for the safer and useful disposal.

From the literature, it is found that there is considerable amount of

sulphate and chloride content present in the tannery and textile effluent (Brent

Smith 1986). Due to the presence of sulphate, it is expected that there may be

sulphate attack in the form of spalling and cracking which may lead to

disintegration of the concrete structures (Brent Smith 1986, Al-Harthy et al

2005). Due to the presence of chloride content there may be a possibility of

chloride attack which may cause corrosion in the reinforcement bars

embedded in the concrete (Glass and Buenfeld 1998). In addition, due to

lower pH (acidity nature) there may also be corrosion of reinforcement bar

3

embedded in the concrete. So the effect of sulphate and chloride content in the

tannery and textile effluents on the properties of concrete have to be examined

thoroughly. Hence in this present research an attempt has been made to study

the effects of sulphate attack on the concrete, chloride attack on the concrete,

corrosion of steel reinforcement embedded in the concrete etc in detail.

To obtain necessary data, several reinforced concrete wharf

specimens are prepared and laboratory tests have been carried out to

determine the concrete properties. The first chapter gives the details about the

introduction, literature review, objective and scope of the project. The second

chapter gives details about experimental methods followed in the study. The

third chapter gives details about results, discussions and cost benefit ratio of

the study. The fourth chapter gives details about conclusion of the study.

1.2 REVIEW OF LITERATURE

Many investigators have studied and reported on various properties

of the concrete prepared using different type of waters and admixtures. This

chapter reviews the available important studies on the various properties of

the concrete such as compressive strength, tensile strength, flexural strength,

sulphate attack, chemical attack, corrosion of the reinforcement bar embedded

in the concrete, concrete degradation, reliability assessment etc and are

discussed in detail.

Kaushik and Islam (1995) prepared and cured the concrete samples

using sea water. They examined the concrete properties such as setting time,

compressive strength of the concrete, corrosion of reinforcement bar

embedded in the concrete and chloride ion penetration of the concrete over a

period of 18 months. They reported that the compressive strength of the

concrete samples prepared using the sea water was less than that of the

4

concrete samples prepared using the potable water. The setting time was

prolonged for the concrete sample prepared by using the sea water. The

corrosion of reinforcement bar embedded in the concrete and chloride ion

penetration were more in the concrete specimen cast using the sea water.

Kilinckale (1997) conducted the experiment by preparing the

concrete specimens adding silica fume, rice husk ash, blast furnace slag and

fly ash as 20% replacement of portland cement. After 28 days of curing, the

concrete specimens were immersed in 5% magnesium sulphate solution and

in 5% hydrochloric acid solution separately. The effects due to sulphate attack

and chemical attack (hydrochloric acid) were measured based on the

reduction in the compressive strength and the loss of weight of the concrete

after 56 days. He reported that the compressive strength of the concrete

specimen blended with pozzolanic material such as fly ash, silica fume, rice

husk ash and metakaoline etc subjected to sulphate attack and chemical attack

was greater than that of the conventional concrete. The loss of weight of the

concrete specimen was less in the concrete blended with pozzolanic material

than that of the conventional concrete. The increase in the compressive

strength and the decrease in the loss of weight of the concrete specimen are

due to the reduction in porosity and increase in binding capacity of the

concrete.

Khatri et al (1997) ascertained that durability of the concrete

structures mostly depended on the permeability of the concrete and not on the

chemistry of cement. He appraised the sulphate attack of concrete by

exposing the concrete specimen to 5% sodium sulphate (Na2So4) solution and

noted that there was considerable loss of weight and reduction in the

compressive strength of the concrete. By the addition of silica fume with the

concrete specimen, the pores in the concrete specimen were reduced. As a

result the permeability of the concrete was reduced and it leads to the decrease

5

in the loss of weight and increase in the compressive strength of the concrete.

He reported that the resistance to sulphate attack was offered by the concrete

specimen blended with high slag cement and 7% silica fume.

Yilmaz et al (1997) have investigated the influence of the sulphate

ions and the effect of pH on the strength of the concrete and the corrosion of

reinforcement steel embedded in the concrete. The concrete samples were

prepared and cured with water having different sulphate ion concentrations

(standard, 400 ppm and 3500 ppm) and distilled water. Then the concrete

samples were exposed to the natural environments for a period of 90 days.

They reported that the compressive strength of the concrete sample decreased

as the sulphate ion concentration increased. The corrosion of reinforcement

steel embedded in the concrete prepared and cured in higher sulphate ion

concentration solutions was higher than that of the concrete prepared and

cured using distilled water.

Glass and Buenfeld (1998) evaluated the transport of the chloride

ions using diffusion cell and developed an exemplar for concentration profile

and duration of penetration of the chloride ions in the concrete. They reported

that the major factor affecting the service life of concrete structure was the

transport of chloride ions through the concrete which leads to chloride attack

and further leads to corrosion of reinforcement bar embedded in the concrete.

They concluded that the concrete structure with higher penetration of chloride

ions for longer duration was affected more than that of the concrete with

lower penetration of chloride ions for shorter duration.

Luping Tang (1999) determined the chloride ion diffusion through

the concrete by measuring the counter electrical potential, ratio of cation

velocity to anion velocity and friction co-efficient. He observed that the

important factor affecting the life of concrete structure was the transport of

6

chloride particles and other micro particles through the concrete. The

transport of such particles leads to the chloride attack and the corrosion of

reinforcement embedded in the concrete which finally resulted in structural

damage of the structure. He analytically derived the formula for the rate of

diffusion of chloride particles through the concrete specimen.

Young et al (1999) studied the sulphate attack on the high strength

concrete blended with silica fume by immersing the concrete samples in

magnesium sulphate and sodium sulphate solution separately. They observed

that there was reduction in the compressive strength of the concrete due to the

sulphate attack. They noted that the resistance to sulphate attack on the

concrete blended with silica fume was more than that of the conventional

concrete because of the increased water binder ratio and reduction in pore

structure of the concrete. They reported that the compressive strength of the

concrete blended with silica fume was higher than the conventional concrete.

Bing Tian and Cohen (2000) carried out X-Ray analysis and

chemical analysis of the concrete samples to study the effect of the sulphate

attack on the concrete. The sulphate attack was mainly due to the reaction

between the sulphate ions and tricalcium aluminate. This reaction resulted in

the production of ettringite with an increase in volume that resulted in

expansion and subsequent cracking of the concrete. Apart from this, sulphate

ions also reacted with calcium hydroxide and formed gypsum. They

concluded that the ettringite formation during sulphate attack was the main

cause of expansion and deterioration of the concrete.

Gruber et al (2001) examined the properties of the metakaolin

blended concrete such as compressive strength, flexural strength, chloride ion

penetration and expansion due to alkali aggregate reaction of the concrete

over a period of 800 days (more than two years). They observed that the

7

expansion of the concrete due to alkali aggregate reaction, compressive

strength and flexural strength were gradually increasing up to 700 days and

after 700 days it almost became constant which was mainly due to the

decrease in the permeability of the concrete.

Vu et al (2001) have studied the compressive strength and the

sulphate attack of the concrete prepared using various admixtures such as

calcined kaolin, blended kaolin, silica fume etc for a period of 180 days. They

have noticed that by the addition of calcined kaolin, blended kaolin and silica

fume while preparing the concrete, the compressive strength of the concrete

was increased and sulphate attack of the concrete was decreased. They

observed that there was only a marginal change in the compressive strength

and the sulphate attack between 90 days and 180 days of test duration. After

90 days, the variation in the properties of the concrete almost became

marginal.

Ghosh et al (2002 a) reported that the fly ash particles are spherical

in nature and having different size in composition. The size of the fly ash

materials is generally smaller than 200µm and the specific surface area of the

fly ash particles is in the range of 180 m2/kg to 590 m2/kg. The density of the

fly ash is in the range of 1800 kg/m3 to 2900 kg/m3. When fly ash is added

with the concrete there is reduction in the permeability of the concrete and in

turn improving the durability of the concrete structure. This is because of the

fineness and higher density of fly ash particles.

Ghosh et al (2002 b) reported that in China 15% of cement was

replaced with the fly ash for preparing the concrete and in Finland, Ireland,

Japan, Korea, Malaysia, Norway and South Africa 5% of cement was

replaced with the fly ash for preparing the concrete to have better strength and

durability properties of the concrete.

8

Marchand et al (2002) observed that the concrete subjected to

sulphate attack underwent a progressive change in its internal micro structure.

These changes had direct effects on the engineering properties of the concrete

such as swelling, spalling and cracking of the concrete. Due to these changes,

there was a significant reduction in the strength properties of the concrete.

They concluded that by reducing the permeability of the concrete by adding

admixtures, various chemical attacks on the concrete could be reduced and

strength properties of the concrete could be improved.

Li (2003) reviewed and reported that the corrosion of the

reinforcement bar embedded in the concrete is the prevailing factor for the

early and premature deterioration of reinforced concrete structures which

further lead to structural failure characterized by cracking, spalling, and

deflection of concrete.

Woo-Yong Jung et al (2003) examined and observed that the

corrosion of the reinforcement bar embedded in the concrete occurred when

the pH of the concrete was in the range of 11–13. If the concrete had more

chloride ions, it could also induce the corrosion of the reinforcement bar

embedded in the concrete regardless of pH. They reported that the corrosion

due to pH could be minimized by increasing the cover of the concrete.

Adam Neville (2004) determined the sulphate attack on the

concrete by measuring the change in the compressive strength and the flexural

strength of the concrete after exposed to sodium sulphate, calcium sulphate

and magnesium sulphate solutions. He reported that sulphate attack is directly

proportional to the water cement ratio.

Bryant Mather (2004) studied the effect of sulphate attack,

chemical attack, corrosion of reinforcement bar embedded in the concrete and

9

alkali aggregate reaction on the concrete blended with various proportions of

admixtures. The chemical attack and the alkali aggregate reaction on the

concrete were reduced by adding fly ash, silica fume, rice husk ash,

metakaolin, blast furnace slag. Apart from this, addition of the admixture

reduced the corrosion of the reinforcement bar embedded in the concrete. He

suggested that the corrosion of reinforcement bar embedded in the concrete

could be reduced or prevented by coating zinc on the steel reinforcement bar

to be embedded in the concrete before concreting.

Erdogdua et al (2004) studied the chloride attack on the concrete by

immersing the concrete sample in sodium chloride solution and found that

there was a diffusion of chloride particles into the concrete which induced the

corrosion of the reinforcement bar embedded in the concrete. He concluded

that if the permeability of the concrete was reduced, the concrete could be

safeguarded against the chloride attack.

Haque et al (2004) studied the mechanical properties of the

concrete such as compressive strength, tensile strength, modulus of rupture

etc and durability properties of the concrete such as sulphate attack, chloride

attack etc for a period of one year. They observed that when the permeability

of the concrete was reduced by adding admixtures, the compressive strength,

tensile strength, modulus of rupture etc of the concrete were increased and

loss of weight, reduction in mechanical strength due to the sulphate attack and

the chloride attack on the concrete were reduced.

Khatri and Sirivivatnanon (2004) have observed that the variation

in the quality of the concrete was due to different water cement ratio, different

method and level of compaction, different method and extent of curing,

varying thickness of the coating on the concrete (cover depth values) etc.

They concluded that by adopting suitable method for concreting and

10

increasing the cover of the concrete, the service life and the durability of the

concrete structure could be improved.

Nehdi et al (2004) studied the effect of sulphate attack on binary,

ternary, and quaternary blended self consolidating concrete. The fresh

concrete properties such as initial setting time, compaction factor, workability

and compressive strength of the concrete were determined after 1, 7, 28 and

90 days of casting. The sulphate attack on the concrete was determined by

measuring the expansion of the concrete and reduction in compressive

strength of the concrete after immersing the concrete samples in a 5% sodium

sulphate solution for a period of 9 months. They reported that the self

consolidated composite concrete (binary, ternary, and quaternary concrete)

achieved better workability, higher compressive strength, better scaling

resistance and lower sulphate expansion than that of the conventional

concrete.

Olivier Poupard et al (2004) have observed that the corrosion of

steel reinforcement bar embedded in the concrete was the main cause of

degradation of the concrete. Initially, the reinforcement steel embedded in the

concrete was naturally protected from corrosion by the high alkalinity of the

concrete. This alkalinity of the concrete was destructed either by the ingress

of the aggressive ions (chlorides and sulphates present in the water) or by an

acidic environment. They concluded that by giving extra cover to the

reinforcement bar embedded in the concrete, the corrosion of reinforcement

bar embedded in the concrete could be reduced even in the aggressive

environment.

Rui Miguel Ferreira (2004) studied the properties of the concrete

such as alkali aggregate reaction, corrosion of steel reinforcement embedded

in the concrete, permeability and chemical attack. He observed that the

11

properties of the hardened concrete were governed by its micro and macro

structure of the concrete. If the internal structure of the concrete became very

hard, the permeability of the concrete was reduced. In turn it resist the

chemical attack from external sources (e.g., acids and sulphates), within the

concrete (e.g., alkali-aggregate reaction) and other environmental distress

(ingress of moisture through the cracks).

Saricimen et al (2004) studied the effects of using treated effluent

for preparing the concrete as a replacement to potable water. They prepared

the concrete samples using both the potable water and the treated industrial

effluent and allowed the concrete samples for curing in the respective water.

The compressive strength of the concrete was determined after 7, 14, 28 and

90 days of casting. They reported that the compressive strength of the

concrete prepared using treated effluent was higher than that of the concrete

samples prepared using the potable water. The strength of the concrete

samples prepared using treated water was 112% higher than that of the

concrete samples prepared using potable water. The strength of the concrete

samples blended with 8% silica fume using treated effluent was 115% higher

than that of the concrete samples prepared using potable water. There was 8%

to 9% decrease in the setting time of the concrete prepared using treated

effluent than that of the concrete prepared using potable water where as the

setting time of the concrete blended with 8% silica fume prepared using

treated effluent was 10% higher than that of the conventional concrete.

Wombacher et al (2004) observed that the corrosion of

reinforcement bar embedded in the concrete was not initiated under the

alkaline condition. They reported that the concrete cover played a vital role

for preventing the corrosion of steel reinforcement embedded in the concrete

and suggested that by increasing the concrete cover, the corrosion of the steel

reinforcement embedded in the concrete could be delayed.

12

Al-Harthy et al (2005) replaced the potable water with the waste

water obtained from oil production fields and other brackish ground water for

making the concrete samples. They determined the compressive strength of

the concrete samples after 7, 14, 21, 28, 35, 42, 49, 56 and 63 days of casting.

They reported that the compressive strength of the concrete prepared using

waste water was less than that of the concrete prepared using potable water

but the required target mean compressive strength was obtained by the

concrete sample prepared using the water obtained from oil production fields

and other brackish ground water.

Chiara Ferraris et al (2005) observed that the external sulphate

attack on the concrete not only affected the internal structure of the concrete

but also adversely affected the concrete structure by softening and cracking

the outer surface of the concrete. Apart from these observations they also

found out that the sulphate attack was more prevalent in arid regions clustered

with industries.

Eshmaiel Ganjian and Homayoon Sadeghi Pouya (2005) studied

the effect of ingress of the sulphate ions in the concrete specimens prepared

using sea water added with silica fume and granulated blast furnace slag.

They measured the effect of the sulphate attack based on the change in the

compressive strength of the concrete specimen. They reported that the

compressive strength of the silica fume blended concrete was higher than that

of the conventional concrete specimen and the granulated blast furnace slag

blended concrete.

Kapilesh Bhargava et al (2005) reported that the predominant factor

responsible for the deterioration of the concrete was the corrosion of the

reinforcement bar embedded in the concrete. The corrosion of the

reinforcement bar embedded in the concrete damaged the concrete structure

13

by expansion, cracking and spalling of the concrete cover. They also reported

that the structural damage was also due to the loss of bond between the

reinforcement and the concrete and reduction in cross sectional area (due to

loss of weight) of the reinforcement bar embedded in the concrete.

Lee et al (2005 a) have studied and observed the mechanism of

deterioration of the concrete structure subjected to sulphate attack. They

concluded that the mechanism of sulphate attack was due to the chemical

reaction between the hydrates in cement pastes and dissolved compounds

such as sodium sulphate and magnesium sulphate. They observed that the

magnesium sulphate present in the solution induced the deterioration of

concrete which was due to the formation of magnesium gel containing

hydrates (M–S–H gel), as well as gypsum and thaumasite. If sodium sulphate

was present in the solution, the deterioration of the concrete was due to the

reaction of sulphate (So4) ions with the cement paste.

Lee et al (2005 b) have examined the sulphate attack on the

concrete samples blended with 0%, 5%, 10% and 15% metakaolin immersed

in magnesium sulphate solution. They evaluated the sulphate attack on the

concrete based on the visual examination, reduction in the compressive

strength and expansion of the concrete. Based on their experiment results they

reported that the concrete specimens blended with 15% metakaolin showed

lower resistance to sulphate attack due to magnesium sulphate. Where as in

the concrete blended with lower concentration of metakaolin (5%), there were

no remarkable differences in the deterioration of concrete specimens.

Nehdi and Hayek (2005) have studied the effect of the sulphate

attack on the concrete samples made of ordinary portland cement (OPC)

replaced with the pozzolanic materials such as silica fume, fly ash and blast

furnace slag. The concrete samples were immersed in 10% magnesium

14

sulphate (MgSO4) solution and 10% sodium sulphate (Na2SO4) solution. They

monitored the expansion and surface degradation of the concrete samples over

a period of 9 months. They reported that the sulphate attack on the concrete

was characterized by the formation of the white efflorescence on the concrete

surface, scaling of surface of the concrete and crystallization of salts on the

outer surface of the concrete. They concluded that the sulphate attack on the

concrete blended with fly ash and blast furnace slag was less than that of the

non blended conventional concrete.

Poongodi (2005) studied the effects of corrosion inhibitors such as

inorganic anodic inhibitors (calcium nitrite, calcium nitrate), organic cathodic

inhibitors (amino alcohols), amino alcohol based mixed corrosion inhibitor

etc blended with the concrete for reducing the corrosion of the reinforcement

bar embedded in the concrete. She reported that the effect of corrosion of

reinforcement bar embedded in the concrete was considerably reduced by

adding the calcium nitrate as the corrosion inhibitor along with the concrete.

El -Dieb (2006) conducted experiments and measured the

permeability of the concrete for different age durations up to a period of 56

days from the date of preparation of the concrete sample. He reported that the

permeability of the concrete decreased with increase in age duration of the

concrete. Apart from the permeability of the concrete he also observed that

the rate of hydration of cement became slower after 28 days of preparation of

the concrete sample.

Frank Bellmann et al (2006) observed that the concrete was a

material susceptible to the ingress of sulphate ions from the environment and

reported that the deterioration of the concrete due to sulphate attack was

because of the formation of ettringite, thaumasite or gypsum. The

deterioration of the concrete due to sulphate attack was observed based on the

15

loss of weight of the concrete sample and reduction in compressive strength

of the concrete.

Hanifi Binici and Orhan Aksogan (2006) evaluated the sulphate

attack on the concrete blended with high volume ground granulated blast

furnace slag (GGBS) and natural pozzolanic materials (NP) such as fly ash,

silica fume and metakaolin etc. The concrete samples were exposed to 5%

magnesium sulphate solution and 5% sodium sulphate solution. It was

observed that the effect due to sulphate attack on the concrete blended with

ground granulated blast furnace slag (GGBS) and natural pozzolanic materials

(NP) is less than that of the conventional concrete. They reported that

reduction in the compressive strength of the concrete exposed to sodium

sulphate was lower than that of the concrete exposed to magnesium sulphate

solution.

Hossain and Lachemi (2006) studied the deterioration of the

concrete structures due to the presence of sulphate contents in soil,

groundwater and marine environments. They conducted the experiments by

replacing cement with volcanic ash and volcanic pumice for preparing the

concrete. After 28 days of curing, the concrete samples were immersed in

magnesium sulphate solution and sodium sulphate solution separately for a

period of 48 months. They conducted the experiments such as compressive

strength, X-ray diffraction, differential scanning calorimetry, mercury

intrusion porosimetry and rapid chloride permeability to determine phase

composition, pozzolanic activity, porosity and chloride ion resistance. The

deterioration of concrete due to sulphate attack and corrosion of reinforcing

steel embedded in the concrete were evaluated based on the loss of weight of

the concrete and reinforcement steel embedded in the concrete. They reported

that the performance of the blended concrete was better than that of the

conventional concrete.

16

Ismail Yurtdas et al (2006) observed in his experimental study that

the drying process of the concrete brought about desiccation shrinkage which

was due to the increase in suction of moisture, reduction in permeability and

variations in pressure (due to self weight and live load on the concrete

structure). They reported that the mechanical properties of the concrete such

as compressive strength and flexural strength almost became constant after

one year.

Jieying Zhang and Zoubir Lounis (2006) have observed and

reported that the corrosion of the reinforcement steel embedded in the

concrete lead to fracture of concrete by means of cracking, delamination,

spalling of the concrete cover. Apart from this reduction in cross sectional

area of the reinforcement bar embedded in the concrete, loss of bond between

the concrete and the reinforcement steel embedded in the concrete, reduction

in strength of the concrete and decrease in ductility of the concrete were also

observed.

Nabil and Al-Akhras (2006) investigated the effect of the concrete

blended with the metakaolin (5%, 10%, and 15% MK) on the sulphate attack

of the concrete. After 28 days of curing, the concrete specimens were

immersed in 5% sodium sulphate solution for a period of 18 months. The

sulphate attack was appraised based on the expansion of the concrete

specimens and reduction in compressive strength of the concrete specimens.

They reported that the concrete specimens blended with 10%, and 15%

metakaolin had higher sulphate resistance than that of the conventional

concrete specimens.

Rongzhen Dong et al (2006) noted that several cracks on the

surface of the concrete foundations that supported the steel tower of the

Luohe Huaiyang high voltage electricity transmission line which was 20 years

17

old situated in North China. To analyze the deterioration mechanism that led

to cracking, field investigations were carried out and several tests were

conducted on the soil and the concrete by electric probe analysis and chemical

analysis. They found that the concentration of sulphates was high in the

surrounding soil and the coarse aggregates present inside the concrete. They

observed that the sulphate present in the outer surface of the concrete was

higher than that of the inner layer of the concrete. They reported that the

sulphate ions penetrated into the concrete and reacted with the cement to form

ettringite, which lead to the cracking of the concrete.

Sideris et al (2006) investigated the sulphate resistance of the fly

ash blended concrete by immersing in a 5% sodium sulphate (Na2SO4)

solution for a period of 24 months. They reported that by the addition of

pozzolanic admixtures (fly ash) while preparing the concrete the sulphate

resistance of the concrete was improved.

Vijayarangan (2006) examined the effect of sulphate attack on the

concrete and measured it based on the change in mass, loss of weight, and

reduction in compressive strength of the concrete. He reported that the

deterioration of portland cement concrete due to sulphate attack was because

of the formation of expansive gypsum and ettringite which caused expansion,

cracking, and spalling of the concrete.

Zhou et al (2006) studied the effect of sulphate attack and acid

attack on the concrete. They prepared the concrete samples with three

different types of cement and immersed in acid solution and sulphate solution

separately. Based on their experimental results, they concluded that there was

more loss of weight of the concrete specimens subjected to acid attack than

that of the sulphate attack. They observed that there was a formation of

18

thaumasite due to sulphate attack where as there was no such formation was

found in the concrete samples immersed in acid solution.

Byung Hwan Oh and Seung Yup Jang (2007) studied and reported

that the presence of chloride ion in the concrete induced corrosion of

reinforcement bar embedded in the concrete which was one of the major

causes lead to deterioration of the concrete structures. They suggested that the

resistance and prevention of the chloride ion penetration in the concrete could

be achieved by adding the admixtures and increasing the cover thickness of

the concrete.

Dehwah (2007) studied and observed that when the concrete was

exposed to the magnesium sulphate and sodium sulphate, they chemically

reacted with calcium hydroxide present in the concrete and formed gypsum

and corresponding hydroxides such as magnesium hydroxide and sodium

hydroxide. Further the effect of the sulphate attack on the concrete due to

magnesium sulphate was higher than that of the sodium sulphate.

Gopalan (2007) studied the effect of sulphate attack, chloride

attack, acid attack and alkali aggregate reaction on the concrete blended with

the fly ash (pozzolanic material). He observed the effects due to sulphate

attack, chloride attack, acid attack and alkali aggregate reaction on the

concrete based on the loss of weight, reduction in compressive strength and

expansion of the concrete. He reported that more resistance was offered by

the concrete blended with fly ash against sulphate attack, chloride attack, acid

attack and alkali aggregate reaction on the concrete. He concluded that by the

addition of fly ash with the concrete the workability was increased, the

permeability was reduced and the bond strength of the concrete was

improved.

19

Jin Zuquan et al (2007) investigated the effect on the concrete

samples immersed in sodium sulphate and sodium chloride salt solution. The

concrete samples were plain cement concrete (conventional concrete) and the

concrete blended with fly ash in various proportions. The concrete samples

were immersed in three types of solutions (3.5% sodium chloride solution,

5% sodium sulphate solution, mixture of 3.5% sodium chloride and 5%

sodium sulphate solution). They measured the effects on the concrete based on

loss of weight and compressive strength of the concrete. They reported that

there was more loss of weight and decrease in compressive strength of the

concrete immersed in the mixture of 3.5% sodium chloride and 5% sodium

sulphate solution than immersed in sodium chloride solution and sodium

sulphate solution separately. The concrete blended with fly ash had

significantly improved resistance to chloride and sulphate ion ingress into the

concrete. The loss of weight and reduction in compressive strength of the

concrete blended with fly ash were less than that of the conventional concrete.

Krishnaswami et al (2007) studied the compressive strength and

flexural strength of the concrete made of cement replaced with 25% of fly ash

and 50% of fly ash. They reported that the compressive strength and the

flexural strength of the concrete blended with 25% of fly ash was more than

that of the concrete blended with 50% of fly ash and the conventional

concrete. The compressive strength and the flexural strength of the concrete

got reduced when the cement was superseded with 50% of fly ash and more

than 50% of fly ash.

Mohd Firdows et al (2007) observed that most of the concrete

structures got deteriorated mainly because of the corrosion of reinforcement

bar embedded in the concrete. The corrosion of reinforcement bar embedded

in the concrete was accelerated either by chloride attack or by carbonation of

the concrete or by combination of chloride attack and carbonation on the

20

concrete. They suggested that chloride attack and carbonation on the concrete

could be counteracted by adding pozzolanic materials such as fly ash, silica

fume, rice husk ash etc.

Salah and Al-Dulaijan (2007) evaluated the performance of plain

cement concrete and blended concrete exposed to magnesium sulphate

solutions, with varying sulphate concentrations, for a period of 24 months.

They prepared the concrete samples using plain cement, cement replaced with

silica fume and cement replaced with fly ash. The concrete samples were

exposed to magnesium sulphate solutions with five different sulphate

concentration of 1%, 1.5%, 2.0%, 2.5%, and 4.0% separately. The sulphate

resistance of the concrete was evaluated based on visual examination and the

reduction in compressive strength of the concrete. They reported that the

maximum deterioration due to sulphate attack was noted in conventional

concrete than that of the concrete blended with silica fume and fly ash. They

concluded that the addition of fly ash with the concrete enhanced the

resistance more to sulphate attack in sulphate rich environments than the

concrete blended with silica fume.

Tamizheselvi and Samuel Knight (2007) reported that the ingress of

chloride ions into the concrete induced the corrosion of the reinforcement bar

embedded in the concrete. The corrosion of the reinforcement bar embedded

in the concrete resulted in staining, rusting and spalling of the concrete due to

the increase in volume of the reinforcement bar because of conversion of iron

into iron oxide.

Tamer El Maaddawy and Khaled Soudki (2007) reported that the

mechanism of corrosion of reinforcement bar embedded in the concrete was

electrochemical in nature. The corrosion of reinforcement bar embedded in

the concrete occurred only when the alkaline environment of the concrete

21

changed to acidic environment. In the acidic environment, iron oxides were

formed at the surface of the reinforced steel embedded in the concrete which

further lead to cracking and spalling of the concrete.

Aggoun et al (2008) studied the effect on the properties such as

setting time and compressive strength of the concrete blended with various

admixtures such as calcium nitrate, tri-ethanolamine and tri-

isopropanolamine. They reported that the concrete specimen blended with

calcium nitrate had an early setting time and a long term development of

mechanical strength properties. The compressive strength of the concrete

blended with calcium nitrate had increased with respect to increase in

duration of the age of the concrete.

Chatveera and Lertwattanaruk (2008) investigated the sulphate

attack on the concrete samples blended with black rice husk ashes (in various

proportions of 5%, 7% and 10%). The concrete samples were exposed to 5%

sodium sulphate solution and magnesium sulphate solution separately. The

sulphate attack on the concrete samples was determined based on the loss of

weight of the concrete, expansion of the concrete and reduction in

compressive strength of the concrete. There was higher loss of weight and

reduction in compressive strength of the concrete blended with 10% of black

rice husk ashes. The expansion and loss of weight of the concrete samples

exposed to sodium sulphate solution was higher than that of the concrete

samples exposed to magnesium sulphate solution.

Dinakar et al (2008) evaluated the properties such as permeability,

water absorption, acid attack and chloride penetration of the concrete

specimens blended with different proportions of fly ash with cement. The

water absorption of the concrete samples was evaluated based on the change

in weight of the concrete sample immersed in water. The concrete properties

22

such as acid attack and chloride penetration were measured based on the loss

of weight and reduction in compressive strength of the concrete. They

reported that the concrete samples blended with high volume fly ash (more

than 40 %) leads to more loss of weight and reduction in compressive strength

of the concrete than that of the conventional concrete when subjected due to

acid attack and chloride attack. The water absorption and permeability of the

concrete sample blended with high volume fly ash were lower than that of the

conventional concrete.

Guerrero et al (2008) studied the flexural strength of the concrete

specimens blended with fly ash. The concrete specimens were immersed in

simulated radioactive liquid waste which was rich in sulphate and sodium

chloride salts for a period of 180 days. They reported that the flexural strength

of the concrete specimen blended with fly ash was higher than that of the

conventional concrete specimen. The concrete specimen blended with fly ash

was stable against erosion when immersed in simulated chloride radioactive

liquid waste. They concluded that the enhancement of properties of the

concrete was due to the formation of non-expansive Friedel's salt inside the

concrete pores.

Nader Ghafoori et al (2008) studied the sulphate attack on the

concrete blended with fly ash by immersing the concrete samples in 5%

sodium sulphate solution. They evaluated the sulphate attack of the concrete

based on the change in length, loss of weight and compressive strength of the

concrete over a period of 270 days. They reported that the change in length,

loss of weight and compressive strength of the concrete samples blended with

fly ash was lower than that of the conventional concrete.

Rajamane et al (2008) determined the load carrying capacity of the

concrete beams blended with the pozzolanic material (fly ash). They reported

23

that the load carrying capacity of the concrete beams blended with fly ash was

more than that of the conventional concrete beams.

Malathy and Subramanian (2008) studied alkali aggregate reaction

of the concrete using cement mortar bars blended with 5%, 10% and 15% of

fly ash. They reported that the cement mortar bars blended with 5% fly ash

(mineral admixture) was sufficient to reduce the expansion of the cement

mortar bar by more than 75%. They concluded that about 80 - 90% of the

expansion of the cement mortar bars due to alkali aggregate reaction could be

controlled by adding the mineral admixtures as a part of replacement with the

cement while preparing the concrete.

Ramesh (2008) used torrent permeability tester for measuring the permeability of the concrete. He determined the permeability of slabs, walls and other prepared test specimens using the torrent permeability tester. Based on the experimental results, he concluded that the penetration of chloride particles, penetration of sulphate particles and corrosion of steel reinforcement embedded in the concrete mainly depends on the permeability of the concrete. It is evident from the literature that the tannery and textile effluents contain more amount of sulphate and chloride content (Brent Smith 1986). When the concrete is prepared using the tannery and textile effluents, sulphate ions and chloride ions may react inside the concrete causing cracking, spalling, and disintegration of the concrete. The chloride ions react with reinforcement bar embedded in the concrete and leads to the corrosion of the reinforcement bar embedded in the concrete. The corrosion of the reinforcement bar embedded in the concrete leads to cracking and spalling of the concrete, excessive deflection, structural failure and finally structural collapse.

24

Omar et al (2003) used brackish water for preparing the concrete

and used the calcium nitrate as the corrosion inhibitor in their work and found

it to be successful in preventing and reducing the corrosion of reinforcement

bar embedded in the concrete. Saricimen et al (2004) used the treated effluent

for preparing the concrete along with silica fume as admixture and noted that

the adverse effects on the concrete prepared using the industrial effluent was

reduced.

The addition of the pozzalonic materials such as fly ash, diatomaceous earth, metakaolin, silica fume, rice husk ash etc can counteract the ingress of the sulphate ions and chloride ions and in turn it reduces the corrosion of the reinforcement bar embedded in the concrete and increases the strength properties of the concrete (Shetty 2003, Malathy 2004, Sideris et al 2006). Gopalan (2007) used fly ash and found the properties such as corrosion of the reinforcement bar embedded in the concrete was reduced and reported that the properties such as sulphate attack, chloride attack, alkali aggregate reaction were counteracted up to some extent. The admixtures such as calcium nitrite, calcium nitrate, amino-alcohols (ethanolamine and N-dimethy-w-ethanolamine) had been used in the concrete and a good improvement in both corrosion and strength properties of concrete were observed (Poongodi 2005). The admixtures such as fly ash, silica fume and rice husk ash had been used to counteract the chemical attacks like corrosion of the reinforcement bar embedded in the concrete and found that chemical attack on the concrete was reduced and strength properties of the concrete were improved (Hanifi Binici and Orhan Aksogan 2006, Mohd Firdows et al 2007). The commercially available admixtures such as webac- 2061, webac 4170, concare etc can be considered for the counteracting the expected chemical attacks.

From the collected literature various tests were conducted up to 800

days and hence in this study, the parameters such as corrosion studies,

chemical attack, sulphate attack, chloride attack, alkali aggregate reaction,

25

permeability and compressive strength etc are studied and observed for a

period of 2.5 years from the date of casting of concrete specimens. In addition

the strength properties of the concrete such as tensile strength, flexural

strength, failure load of the beam etc which have impact on the concrete are

also to be examined.

1.3 OBJECTIVE AND SCOPE OF THE PROJECT

1. To analyze the characteristics of untreated and treated tannery

effluents, untreated and treated textile effluents.

2. To study the effect on the properties of the concrete such as

compressive strength, tensile strength, flexural strength, bond

strength, sulphate attack, chloride attack, corrosion etc using

tannery and textile effluents.

3. Selection and optimization of suitable admixtures to

counteract the adverse effects of using tannery and textile

effluents on the properties of the concrete.

4. To study the properties of concrete such as sulphate attack,

chloride attack, corrosion, chemical attack, alkali aggregate

reaction, leachability of chloride, leachability of sulphate,

permeability, compressive strength, tensile strength, flexural

strength (PCC), failure load (RCC beams) and bond strength

prepared using potable water, tannery and textile effluents

blended with admixtures for longer duration.